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Math Toolbox is designed to help readers apply STEM principles to everyday safety issues. Many readers may feel apprehensive about math and science. This series employs various communication strategies to make the learning process easier and more accessible.
Radioactive materials are common in many workplaces. For example, medical facilities maintain radioisotopes for diagnosis and treatment; manufacturers acquire radioactive sources to sterilize products and identify hidden flaws through nondestructive testing; construction and agricultural establishments keep radioactive devices to measure moisture content and density of materials; research laboratories use radioactive isotopes to trace the movement of gases, fluids and solids; and power companies house radioactive materials in reactors to provide electricity for millions of customers worldwide.
In these and other applications, safety professionals must protect against uncontrolled release of isotopes and ionizing radiation. Figure 1 illustrates the extensive measures that may be required when even small amounts of radioactive materials are inadvertently released into the environment.
It is impossible to completely eliminate radiation exposure because we all receive limited doses from naturally occurring radioisotopes on Earth and from cosmic rays arriving from space. Nevertheless, decades of research have shown that ionizing radiation is hazardous to health. Within the body, radiation breaks apart life-sustaining molecules and creates toxic by-products. If damage is minor, cells may repair themselves. If damage is serious or widespread, cells may die or DNA may be changed in ways that prevent cells from reproducing normally. Intense exposures may cause acute radiation syndrome and death. Less intense but chronic exposures may lead to cancer, cataracts and many other illnesses. It is not possible to specify a safe level of exposure to ionizing radiation, so it is generally recommended that exposures be kept as low as reasonably achievable.
Radioactive Decay
Atoms emit radiation during a process called radioactive decay. To understand the decay process, it is helpful to review some basic concepts of atomic physics.
Atoms are small particles of matter. Every atom belongs to a particular element such as hydrogen, carbon or gold. More than 90 naturally occurring elements have been identified and many more have been created in laboratories. At the heart of every atom is the nucleus (see Figure 2). Within the nucleus reside particles called protons that have a positive electrical...